This invention relates to an apparatus for mounting an outboard motor or a leg portion of a conventional stern-drive motor to a boat.
When racing or cruising in a boat having an outboard motor or stern-drive, it is often desirable to adjust the motor or stern-drive relative to the boat to achieve a desired performance effect. For example, it may be desirable to lower the bow of the boat and raise the stern to increase clearance between the propeller and the ocean bottom below. This can be achieved by tilting the motor into an upward angle of attack thereby lifting the propeller of the motor closer to the surface of the water.
Alternatively, it is sometimes desirable to raise the bow of the boat to cause the boat to plough through the water. This can be achieved by tilting the motor into a downward angle of attack thereby causing the stern of the boat to be driven deeper into the water and raising the bow.
Preferably, the angle of attack of the motor need not be adjusted to raise the motor relative to the bottom but rather, the motor can maintain its angle of attack and yet be lowered or raised relative to the surface of the water. Also, preferably, when racing, the distance between the propeller and the transom can be independently controlled to place the propeller in less or more turbulent water as desired to obtain optimum performance.
Prior art devices such as disclosed in U.S. Pat. No. 4,836,811 to Griffiths et al, U.S. Pat. No. 4,013,249 to Meyer et al, U.S. Pat. No. 4,836,124 to Haasl, U.S. Pat. No. 2,782,744 to Staley, U.S. Pat. No. 4,813,897 to Newman et al and U.S. Pat. No. 3,990,660 to Pipoz each disclose commonly used parallelogram-type motor mounting brackets which permit the angular orientation of the motor relative to the transom of the boat to be maintained constant while the motor is raised or lowered relative to the water. Raising or lowering of the motor, however, causes the motor to also be moved in a horizontal direction and thus the motor cannot be raised or lowered vertically without affecting the horizontal distance between the propeller and the transom.
U.S. Pat. Nos. 4,384,856 and 4,354,848 both to Hall et al, U.S. Pat. No. 4,682,961 to Nakahama and U.S. Pat. No. 4,367,860 to Strang disclose motor brackets which swing the motor through an arc to raise or lower it into the water. The Hall et al patents disclose the use of a trim cylinder to adjust the angle of the motor relative to the bracket during operation. However, it appears that none of these patents discloses an apparatus which permits movement of the motor while maintaining the angular orientation of the motor relative to the transom.
Finally, U.S. Pat. No. 4,673,358 to Iwai et al discloses a motor mounting bracket using a scissor-type of arrangement to rotate a motor.
It appears that each of the above patents have sought to address the problem of mounting a motor to a boat while permitting movement of the motor to adjust performance or to remove the motor from service. However, each of these patents relates to a device or devices for use with an outboard motor only and furthermore, none of the devices appear to permit motor adjustment both horizontally and vertically while maintaining the angular orientation of the motor constant.